As we continue to build on our monthly articles pertaining to responding propane incidents, we wanted to place the focus on basic response priorities The first and most important aspect is that when responding to any type of flammable gas call you need to ensure you have proper PPE prior to entering a structure to investigate the incident. This includes proper bunker coat and pants, SCBA, helmet, gloves, hood, and boots. There are documented cases where firefighters have become complacent to responding to these types of incidents and have not worn the proper PPE which has resulted in serious injuries. We must remain disciplined and wear the appropriate PPE for this type of incident.
The second aspect is to ensure you have the proper equipment to investigate a flammable gas leak such as propane. The primary item needed is a combustible gas indicator (CGI) to detect the presence of a flammable gas. It is important to follow the manufacturer recommendations and ensure the device’s readiness prior to monitoring for a flammable atmosphere. It is also crucial to understand the limitations for your CGI and your capabilities to investigate this type of incident.
A third aspect that is critical with responses to flammable gas calls, like any other hazmat call, that the personnel involved are properly trained to the level of response required, and that any specialized equipment that is utilized is in good working order and has been properly maintained and/or calibrated prior to use.
Once you have the proper PPE and equipment and are ready to investigate if there is a flammable gas present, there are a few items that you need to remember to stay safe:
- Do not operate light switches or any other item that may cause an ignition if a flammable gas is present.
- When responding to a potential flammable gas incident within a structure ensure that the structure has been evacuated prior to investigating.
- If you detect a flammable gas within a structure isolate the source and perform ventilation (natural).
- If you detect a flammable gas, notify the proper utility companies.
A further point of discussion this month is if you are performing air monitoring of the structure for flammable gas there are a few items you need to remember to operate in a safe and efficient manner. One of the main issues is understanding where the flammable gas may be and ensuring that you are monitoring accordingly. As an example, propane has a relative gas density of 1.55. This means that it will sink to lower areas such as basements or closer to the floor. As a reminder the relative gas density will tell you if a substance is lighter or heavier then air. This means that anything that is below 1.00 will be lighter than air and anything above 1.00 is heavier than air. This information can be found in resources like the NIOSH Pocket Guide to Chemical Hazards and the Wiser app. Another important item to be aware of is what the correction factor is for the monitor that you are using. For example, for a propane incident, if you are using a monitor that has the standard four gases and a PID built into it, then you will potentially see readings on both the LEL and the PID. In this case you need to understand what the correction factor is in order to know what the true readings are.; As you continue monitoring it is crucial that you have a systematic approach and cover the entire area. If during your systematic monitoring your monitor goes into alarm, then ensure that you follow the procedures that have been established by your organization.